    Patent Document 1: JP-A 2006-104448    Patent Document 2: JP-A 2003-159696    Patent Document 3: JP-A 2003-210957    Patent Document 4: JP-A 2004-49957    Non-Patent Document 1: “Microreactor: Synthesis Technology in New Age”, supervised by Junichi Yoshida, CMC Publishing Co., Ltd.    Non-Patent Document 2: X. F. Zhang, M. Enomura, M. Tsutahara, K. Takebatashi, M. Abe “Surface Coatings International Prat B: Coatings Transactions,” Vol. 89, B4, 269-274, December 2006
A microreactor or a micromixer has been provided as a fluid processing apparatus using a fine flow path or a fine reaction container. There is possibility that the microscopic reaction field given by such an apparatus could exert a substantial influence on chemical reactions carried out in beakers and flasks so far (see Non-Patent Document 1).
A typical micromixer and microreactor are provided with a plurality of microchannels of about several ten μm to several hundred μm in diameter and with mixing spaces connected with the microchannels, and in this micromixer and microreactor, a plurality of solutions are introduced into the mixing spaces through a plurality of flow paths called microchannels, thereby mixing the plurality of solutions or allowing a chemical reaction together with mixing. For example, Patent Documents 1 to 3 disclose those structures as microreactors and micromixers. In any of these microreactors and micromixers, at least two types of solutions are passed through fine microchannels respectively and fed as laminar flows having a very thin section, into a mixing space, and in this mixing space, two solutions are mixed and/or reacted.
There are many advantages in microreactors and systems thereof, but as the micro flow path diameter is decreased, a pressure loss is inversely proportional to the biquadrate of the flow path. That is, such high feeding pressure is necessary that a pump making possible to feed a fluid cannot be available. In the case of a reaction accompanied by separation, there is a problem that a microwave flow path is blocked by clogging of a flow path with a product or bubbles the reaction generates. Further, it is also a problem that since the reaction fundamentally depends on speed of molecular diffusion, a microscopic space is not effective or applicable to every reaction, and actual attempts of the reaction are required by trial and error, then good results are selected. Scaling up has been coped with a method of increasing the number of microreactors, that is a numbering-up system, but the number of microreactors which can be comprised is limited to several dozen, thus inherently aiming exclusively at products of high value. The increase in the number of devices leads to an increase in the absolute number of failure causes, and when the problem of clogging or the like actually occurs, it can be very difficult to detect a problem site such as a failure site.
As shown in an apparatus in Patent Document 4 filed by the present applicant, there is an apparatus wherein a fluid containing a material to be processed (a first fluid) is introduced between the processing surfaces, at least one of which rotates relative to the other, and which are capable of approaching to and separating from each other, and at least another fluid containing a material to be processed (a second fluid) is introduced between the processing surfaces from another flow path that is independent of the flow path for introducing the first fluid and is provided with an opening leading to the processing surfaces, whereby the two fluids are reacted by mixing and stirring between the processing surfaces. By using this apparatus, improvement on speed of temperature homogenization, improvement on speed of homogenization of concentration, and reduction in processing time in support of molecular diffusion, which have been attempted by conventional micro reactors, can be achieved more effectively than ever.
However, in the case that processing was done between the processing surfaces by using the apparatus based on the above-mentioned mechanism, if a transverse area of the outlet part in the flow path of the second fluid introduced between the processing surfaces was too large, sometimes there has been a case that efficient stirring and mixing of the second fluid, introduced between the processing surfaces, with the first fluid could not be effected between the processing surfaces. Specifically, for example, in the case that the first fluid introduced between the processing surfaces capable of approaching to and separating from and rotating relative to the other is made to a thin film between the processing surfaces, when the second fluid is introduced between the processing surfaces from another flow path independent of the flow path of the first fluid, the second fluid is introduced in such a manner to cut into the thin film of the first fluid between the processing surfaces, and thereafter the first fluid and the second fluid are mixed by stirring between the processing surfaces. At that time, sometimes there has been a case that flow of the second fluid flowing from the outlet part of the flow path to introduce the second fluid and having the flow width which was almost the same as or larger than the aforementioned outlet part diameter existed between the processing surfaces. Accordingly, efficient contact with the first fluid does not take place inside the second fluid flow, thereby insufficient stirring and mixing has been occasionally resulted. In addition, when a reactant contained in the first fluid is intended to be reacted with a reactant contained in the second fluid between the processing surfaces, because the first fluid and the second fluid are not contacted efficiently, there has been a case that the reaction could not be completed totally between the processing surfaces and there has been a possibility that unreacted materials might be discharged as they were from between the processing surfaces.